I'm a bit late on my opinion of the ruler. I have 3 of them - the add a quarter 6", 12" and the add an eighth for the tiny pieced areas. I love love love my rulers. I use them for more than paper piecing too. I have been known to flip them over and use as a regular ruler for some things - I can put my finger right along the side of the lip and then cut.
I bought the 12" first and found it too long for most piecing so I got the 6" one. I use them both though because sometimes the 6" just isn't long enough. I find it slower to scissor cut after each piece I sew - so for me, it's one of my favorite rulers
